Lithopone and process for producing same



Patented Sept. 21, 1926.

1,600,773 1 uNman isrsras qmranr :oFFica.

wILLIAM J; onnmn; or naurr iuo nn.

p mnarriaivn, Assre'n'on TO THE Gunner: com- PANY, or sr.- HELENA, summons, maavmmn,

A" CORPORATION OF OHIO.

- m'rnoroim AND rnocnssronsnitonncmo sum.

R0 Drawing. [Original applicatlondfiled.epten1ber 26,1924, sci-in. 740,086. Divided and can appli cation-filed November 16,

The resent invention relates to a methods.

of pro ucing an improved lithopone.

of zinc 'sul hate (ZnSO and barium sulphide, (Ba are employed,-and a co-precipitate of zinc sulphide (ZnS) and barium sulphate (BaSO is obtained. The precipsulphate solution,

itate istreated in accordance with the well known practice in the art, for the production of lithopone.

I am' aware of the fact that attempts have heretofore been made to improve the .charactor of lithopone. For instance, ultra marine blue has been added to the same to improve its color. To improve its light resistance, phosphates, or alkaline earths, have been added. 4

I have discovered that the properties of the lit-hopone may be greatly improved by the addition thereto of a titanium compound, such .as titaniumoxide (TiO The manner in which, the titanium compound is to be combined with the lithopone, may vary.

I contemplate adding the titanium compound, such as titanium oxide, to a zinc sulphate solution, for producing a suspension in such solution. The barium sulphide solution is now introduced into the suspension of the titanium compound, in the zinc and the mass is thoroughly stirred. A co-precipitate of zinc sulphide and barium sulphate is obtained, with.

pone pigment will be present the titanium compound carried down. The titanium compound is preferably added 1n twenty parts byweight of the same will be. present'in the final product, and the lithoin about eighty to ninety-five parts by weight. However, the proportions may be slightly varied beyond these limits.

The mixture thus obtained, is filter pressed, muflied, quenched in water, ground wet, filter- PI'GSSGdfdI-ifld, and ground. It is then ready for packing in" For the like, forshipment.

I also. contemplate adding the titanium compound, such as titanium oxide, either 1925. Serial No. 69,503.

suspension or ii -the powdered form, to freshly precipitated lithopone. In either case the mixture, thus obtained, is filter pressed, mufile'd, quenched in water, ground wet, filter pressed, dried, and ground. It is then ready for packing in cans, or the l ke, forsh1pment.. In this process, the titanium compound is added in such proportions that it is present in the final prod- I uct in from five to twenty parts by weight, while the lithopone is present infrom eighty to ninety-five partsby weight.

The improved litho one pigment produced, is a fine white hthopone, containing from about five to. twenty per cent weight of the titanium compound, with respect to the total weight of the mass. The

product has a high resistance to light, and

a greatly increased covering ca aolty, with a marked improvement over t e ordinary commercial lithopone, with respect to weather resistance. It also shows a marked improvement in behavior when ground with oils, as it does not tend to liver or harden.

It is to be understood that the forms of my invention herewith shown and 'de scribed, are to be taken as preferred examples of the same, and that various changes may be resorted to in the order of the steps of the methods, and that chemical a equivalents may be, employed, without de so I parting from the spirit of my invention, or

the scope of the subjoined claims.

Having thus described my invention, what I claim is 1. The method of producing an improved lithopone pigment, which comprises subjectin a zinc sulphate solution to the action of a arium sulphide solution in-the pres enceot titanium oxide, whereby the-constituents of. lithopone are obtained with the added titanium oxide, and treating the mass thus obtained for producing the completed lithopone.

2. The method-of producing an improved lithopone pigment which comprises the steps of subjecting a ziric sulphate solution to the action of a barium sulphide solution in the presence of titanium oxide.-

3. The method of producing an im roved pigment comprising the steps of efiectmg the preclpitation of lithopone m the presence of titanium oxide. I

4. The method of producing an improved lithopone pigment, comprising adding titanium oxide to a zinc sulphate solution, for producing a suspension of the titanium oxide insuch solution, mixing the result- 5 ant liquid mass with abarium sulphide solution whereby a emprecipitate of zinc sulphide and barium sulphate is obtained with the titanium oxide carried down, and treitting the resultant product for producing completed lithopone. Y 10 In testimony whereof I afiix my signature.

WILLIAM J. OBRIEN. 

